Method for establishing high-nickel ductile iron material exhaust manifold heat engine service life prediction model

Abstract

The invention belongs to the technical field of engines, and discloses a method for establishing high-nickel ductile iron material exhaust manifold heat engine life prediction model. The method comprises: carrying out heat engine fatigue tests of high-nickel ductile iron material test bars under different design working conditions, and obtaining a stress-strain hysteresis curve of each test bar inthe heat engine fatigue life and half life cycle; obtaining a first parameter group of each test rod according to the stress-strain hysteresis curve; and according to the first parameter group, determining an Ostergren model, a three-parameter power function energy method model and a simplified energy method model. The method has the beneficial effects that heat engine fatigue life prediction iscarried out on the gasoline engine high-nickel ductile iron material exhaust manifold, the deviation is within two times of the line, and the engineering design requirement can be met; the problem that a gasoline engine high-nickel ductile iron material exhaust manifold heat engine fatigue life prediction model is lacked is solved, a heat engine fatigue life prediction method is solidified, and life prediction automation and standardization are achieved.

Description

technical field [0001] The invention relates to the technical field of engines, in particular to a method for establishing a heat engine life prediction model for exhaust manifolds made of high-nickel ductile iron materials. Background technique [0002] Gasoline engine supercharging technology leads to an increase in the heat load of the exhaust manifold structure, an increase in the temperature amplitude and mechanical load amplitude, and the risk of thermal fatigue cracking failure of the exhaust manifold is becoming increasingly prominent. The most effective way to eliminate this hidden danger is to In the manifold design stage, thermal engine fatigue life prediction and support structure optimization design are carried out. The prediction of thermal engine fatigue life needs to define a suitable prediction model and model parameters. The parameters of the life prediction model are obtained through complex numerical fitting of a large number of thermal-mechanical fatigu...

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Problems solved by technology

Therefore, the exhaust manifold thermal engine fatigue life prediction model and its parameter definitions are the core secrets of the enterprise and cannot be obtained

[0003] In the existing related technologies, there is no prediction of the thermal engine fatigue life of the high-nickel nodular iron material exhaust manifold of the gasoline engine. Only the plastic strain is used to evaluate the thermal engine fatigue of the steel exhaust manifold. Combined heat engine fatigue life prediction model to assess the fatigue life of gasoline engine exhaust manifold heat engine

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